Jonathan Tilly may go down in history as the scientist who rewrote conventional wisdom about a woman’s biological clock.

Tilly, a Harvard Medical School researcher, was initially investigating why reproductive cells sometimes die in the ovaries. Along the way, the founder of OvaScience Inc. discovered that stem cells in ovarian tissue could form new eggs or be used to rejuvenate a woman’s existing eggs — a finding that could increase the chances of older women having babies.

The study unleashed a storm of controversy among fertility experts, some questioning Tilly’s methods. “His work totally upsets the norm that has been accepted for decades, and anyone that does this, especially with the confidence and exuberance that Tilly exudes, will inevitably be challenged,” said reproductive endocrinologist Kelle Moley at Washington University in St. Louis.

Tilly, 50, also directs a center for reproductive biology at Massachusetts General Hospital. “We are a long way from actually reproducing a newborn infant, but for the first time, managing, and even possibly rewinding, the biological clock is within our reach,” he said.